This invention relates to novel, anhydrous compositions that are useful as ultraviolet-light ("UV-light") screens for mammalian skin. This invention also relates to methods of inhibiting or preventing UV light-induced skin damage by administering an effective amount of the novel compositions to the skin of a mammal in need of such inhibition or protection.
U.S. Pat. Nos. 5,445,815 and 5,676,934, both to Siegfried, refer to powder-based UV-light screens. Powders comprise particles that are separated from one another by some distance. When applied to a surface, such as mammalian skin, powders do not form a uniform layer. That powders often comprise particles of non-uniform size exacerbates this problem. Accordingly, UV-light screens that are powder-based are less efficient that UV-light screens than those that form uniform layers when applied to a surface and, accordingly, provide relatively lower sun-protection factor ("SPF") values when applied to the skin. In addition, powders often impart an unpleasant, chalky texture to a surface. When applied to skin, especially where the user is exposed to sunlight, powders absorb perspiration and become "cakey," imparting an unpleasant sensation to the skin. Furthermore, powders are easily removed from the skin by washing or bathing, which also removes any UV-light screen contained in the powder.
U.S. Pat. No. 5,204,090 to Han relates to waterproof UV-light screening compositions that comprise water-insoluble ether solvents. Application of these types of ether-based formulations to the skin leaves a greasy film that is not only unpleasant to the touch, but that can also become "sticky," especially when admixed with perspiration, causing particles such as sand or dirt to adhere to the skin.
Accordingly, it is an object of the present invention to provide UV-light screens that overcome the above-mentioned disadvantages.